The present invention relates to an imaging display device, and more particularly to the consolidation in an imaging display device between an imaging portion for converting a light signal into an electrical picture signal and a picture display portion for converting the electrical picture signal into a picture.
Heretofore, an imaging device such as a camera for a video tape recorder has structurally included a portion for converting a light signal into an electrical picture signal and a portion for displaying the electrical picture signal. Used as the former is an image pickup tube which utilizes cadmium selenide (CdSe), amorphous silicon or the like, an imaging device in which MOS transistors and photodiodes or phototransistors are combined, or an imaging device which employs charge coupled devices (CCDs). The latter serves to monitor a picture under imaging or a picture recorded in the VTR, and an electron beam cathode-ray tube (CRT) is chiefly used therefor. In recent years, the LSI implementation of electronic circuits, improvements in a magnetic recording system, etc. have been made in order to render the whole device small in size and light in weight. Regarding the camera, however, in spite of endeavors for the miniaturization of the CRT for monitoring the picture, it is the present situation that the miniaturization of the whole camera is difficult due to the essential structure of the CRT.
Here, a miniaturized and thinned display device can be constructed as a monitoring picture display device by applying an electrooptic material such as liquid crystal and electroluminescent or electrochromic material. Even in this case, it results in a large occupying volume to separately prepare the picture display device and the imaging device and to build them into the camera. Further, a peripheral circuit such as driver circuit, and wiring leads for connecting elements are required, so that the miniaturization of the device cannot be expected much.
To the end of solving such problems, a liquid crystal display device disclosed in Japanese Laid-open Patent Application No. 56-85792 has been proposed in which a liquid crystal layer is held between substrates, and one of the substrates is formed with photosensitive elements, thereby to permit inputting/outputting with a pen.
The prior-art example has its usage limited to the inputting/outputting with the pen, and cannot be used as the monitor of the imaging device. More specifically, in constructing the imaging portion and the picture display portion on an identical device, there are required two systems of light; light which enters the imaging portion from a subject to be imaged, and light with which an imaging person looks at the picture display portion in order to monitor the picture. In the prior-art example, such two systems of light incide on and reflect from only one surface of the substrate. Therefore, the proposed device cannot be used as the monitor of the imaging device.
Another problem concerns the fact that one picture element is composed of an imaging part and a picture display part. When it is intended to execute the imaging and the picture display part with only one surface of the substrate, both parts share the areas of picture elements, and the effective areas of the imaging portion and the picture display portion become small.